Electronic relay circuit



Jan. 31, 1961 F. w. VIEHE ELECTRONIC RELAY CIRCUIT 5 Sheets-Sheet 1Original Filed May 29. 1947 Jan. 31, 1961 F. w. VIEHE ELECTRONIC RELAYCIRCUIT Original Filed May 29. 1947 5 Sheets-Sheet 2 zwmmn. W We Jan.31, 1961 F. w. VIEHE 2,970,291

ELECTRONIC RELAY CIRCUIT Original Filed May 29. 1947 5 SheetsSheet 3MQGNETIZRTION I 1 I I i l l l l I MHGNE TIZING F OECE FIG. 1.

FIG. 2.

INVEN TOR.

RTTOENEV Jan. 31, 1961 F. w. VIEHE ELECTRONIC RELAY CIRCUIT 5Sheets-Sheet 4 Original Filed May 29, 1947 lu nllIllilllfllbwl PI Qprime/v5) Jan. 31, 1961 F. w. VIEHE 2,970,291

ELECTRONIC RELAY CIRCUIT Original Filed May 29, 1947 5 Sheets-Sheet 5 TPUL s5 STANDARD/IE4? m0! ULSE STPNDREOIZER 0 o a M W'Z BY QTTOQNEVUnited States Patent ELECTRONIC RELAY CIRCUIT Frederick W. Viehe, LosAngeles, Calif., assignor to International Business MachinesCorporation, New York, N.Y., a corporation of New York Continuation ofapplication Ser. No. 232,525, June 20, 1951, which is a continuation ofapplication Ser. No. 751,422, May 29, 1947. This application June 28,1954, Ser. No. 439,579

107 Claims. (Cl. 340-1725) My invention relates to electric circuitsemploying relays and more particularly to electronic relay circuits andto memory systems for such circuits. This application is a continuationof my prior application Serial No. 232,525, filed June 20, 1951, whichapplication was a continuation of my previous prior application SerialNo. 751,422, filed May 29, 1947. Applications Serial No. 232,525 andSerial No. 751,422 are now abandoned.

In many electrical systems, electric discharge devices, whether they beof the vacuum type or of the gaseous discharge type, are used as relaysfor a wide variety of control purposes. For example, such relays areused in accumulator circuits or transfer circuits of calculatingmachines. Such relays are also used in sequence-timing circuits forcontrolling various manufacturing operations. In addition, they are usedfor generating pulses in predetermined relationship in intelligencetransmission systems, such as television and teletyperwriter systems, orthe like. In many other applications, such relay means are used tocontrol the application of large quantities of electrical power.Instances of such applications include inverters and welding machines.

The electric discharge devices used in such electric circuits areadapted to be operated and restored while energized and the devices arealways either normally operated orrestored while de-energized. Suitablemeans are provided in such circuits for changing each electric dischargedevice from its operated condition to its restored condition, and viceversa, while the electric discharge device is suitably energized; andsuitable means are also provided for energizing and tie-energizing thecircuits. In the conventional electronic relay circuit, if the circuitbecomes de-energized for any reason whatever, information regarding thelast previous condition of each of the relays prior to de-encrgizationis lost forever, or, at least, cannot be ascertained without greatdifliculty. After re-energization of such systems, the subsequentoperation and restoration of the various relays therein bears nopredetermined or controlled relationship to the last set of conditionsexisting prior to decnergization. This means, for example, that in thecase of a calculating machine, the solution of a problem which has beeninterrupted by de-energization of the calculating machine must becommenced anew when the calculating machine is re-energized. It alsomeans that in many other cases, a deviation from the normal sequentialoperation is likely to occur after the sequence is interrupted byde-energization of the relay circuit, resultIng in poor work or otherundesirable effects.

Accordingly, it is a general object of my invention to provide anelectronic relay circuit with a memory system which permits rememberingthe last prior condition of the respective relay means therein after therelay circuit is de-energized for any reason without resorting tomechanical means.

Another general object of my invention is to provide an electronic relaycircuit with means for recalling the ice last prior condition of therespective relay means therein when the circuit is re-energized.

Another object of my invention is to provide a sys tem for de-energizingvarious cascaded stages of an electronic calculating machine whereby thelast prior condition of the respective sections thereof is remembered.

Another object of my invention is to provide a system for re-energizingvarious cascaded sections of an electronic calculating machine in such away as to permit the recall of the last prior condition of therespective sections therein.

Another object of my invention is to provide an improved means forcoordinately operating and restoring various inter-connected sections ofan electronic relay circuit.

Another object of my invention is to provide an improved means forestablishing a predetermined set of conditions in the various sectionsof an electronic relay circuit.

Another object of my invention is to provide an improved means forchanging the condition, either operated or restored, of a relay meansaccording to the prior history of the circuit in which it is arranged.

Another object of my invention is to provide an improved means forzeroing an electronic calculator.

Another object of my invention is to provide an improved means fortransferring counts from one stage of an electronic calculator toanother stage therein.

Another object of my invention is to provide a control circuit includingrelay means associated with an electronic relay system having memorymeans therein, which control circuit is adapted for de-energizing andreenergizing said system automatically to facilitate recall of the lastcondition thereof prior to de-energization.

Another object of my invention is to provide an electronic relay circuitwith improved actuating means.

Another object of my invention is to provide a improved electronictrigger circuit.

A further object of my invention is to provide a magnetic device whichis adapted to be magnetized according to the last prior condition of anelectronic relay circuit in which it is arranged when that circuit isdeenergized.

A further object of my invention is to provide a magnetlc device whichis adapted to facilitate recall of the last prior condition of anelectronic relay circuit in which it is arranged when that circuit isre-energized.

A further object of my invention is to provide a transformer utilizing acore composed of a material having appreciable magnetic retentivity foroperating or restoring a trigger circuit in which the transformer isarranged, according to the prior history of the core.

A still further object of my invention is to provide an electronic relaycircuit of the ring type with an improved means for sequentiallyoperating various sections of the ring.

A still further object of my invention is to provide an improved pulsestandardizing circuit.

A still further object of my invention is to provide means forautomatically actuating an electronic relay circuit after it has beenre-energized in such a way as to recall its last condition prior tode-energization.

And a still further object of my invention is to provide means forenergizing and de-energizing an electronic re'ay circuit withoutinadvertently actuating any of the sections thereof.

While the principles involved in my invention may be applied to varioustypes of electronic control circuits, for the purpose of illustrationthey will be described hereinbelow with particular reference to theirapplication to an electronic counter, and with particular reference tocounters utilizing electric discharge devices as relay means. However,it is to be understood that these principles may also be applied toother types of electronic relay circuits and to other types of relaymeans so that the disclosure of the specific application of theseprinciples to electronic counters is not to be considered a limitationof the invention thereto. Accordingly, other objects of my invention,together with numerous advan tages thereof, and also other applicationsof my invention to other types of electronic relay circuits, will becomeapparent in the course of the following detailed description of theinvention as applied to electronic counters.

Referring to the accompanying drawings:

Fig. 1 is a wiring diagram of a two-stage scale-of-four electroniccounter incorporating features of my invention;

Fig. 2 is a wiring diagram of auxiliary circuits associated with theelectronic counter of Fig. 1',

Fig. 3 is a rudimentary wiring diagram of the trigger circuit of thetype used in the electronic counter of Fig. 1;

Fig. 4 is an isometric sectional view of a transformer unitincorporating features of my invention;

Fig. 5 is a graph representing various magnetic characteristics of amagnetic core used as a memory element in the transformer of Fig. 4;

Fig. 6 is a wiring diagram of a ring circuit used as a scale-of-fourcounter, together with its associated auxiliary circuits, incorporatingfeatures of my invention;

Fig. 7 is a wiring diagram of an electronic counter of the thyratrontype, together with its associated auxiliary circuits embodying featuresof my invention; and

Fig. 8 is a diagram illustrating the manner of assembling the drawingsof Figs. 1 and 2 to represent a complete electronic counter togetherwith its auxiliary circuits.

Referring to the drawings and more particularly to Figs. 1 and 2, thereis illustrated an electrical counter embodying features of my inventionand comprising two scale-of-two counting stages 10 and 11 connected incascade and provided with memory elements and suitable control circuitsby means of which an indicated count may be remembered and recalled inthe event that the counter becomes de-energized.

Construction of counter Each of the counting stages comprises twosections which are arranged to be alternatively operated and restored,the first stage 10 including first and second sections S and S", and thesecond stage 11 comprising third and fourth sections 8" and S" Forconvenience, similar elements in the four sections are indicated in thefollowing description by the same legend such as a letter but eachcarries a different superscrip or to indicate whether it is in thefirst, second, third or fourth section respectively, and wherever thedescription applies to any such element in all sections, the legend isgiven without a superscript.

Each of the sections includes relay means in the form of an electricdischarge device. Preferably these devices are negative-transconductancepentodes P. Each of the pentodes P comprises five electrodes, namely, acathode K, a control grid CG, a screen grid 56, a suppressor grid G, andan anode A. Suitable e ectrode potential supply circuits are associatedwith the various electrodes in order to maintain each pentode P stablyoperated in a relatively conducting condition or stably restored in arelatively non-conducting condition, reference here being made toconduction or non-conduction of current to the anode A. Each pentode Pis operated as a negative transconductance tube so that an increase inbias from its normal value by application of a negative pulse theretorenders the pentode conductive (i.e., operated) and a decrease in biasfrom its normal value by application of a positive pulse thereto rendersit non-conductive (i.e., restored).

A grid circuit GC is associated with the control electrode C6 of eachpentode P, each such grid circuit GC including two grid controlcircuits. One of the grid control circuits 0C is an operating circuitdesigned to increase the normal bias on the control electrode C6 of theassociated pentode P so as to change this pentode from a restoredcondition to an operated condition when the operating circuit issuitably actuated. The other grid control circuit SC is a restoringcircuit and serves to reduce the normal bias on the control electrode CGof the associated pentode P so as to change this pentode from anoperated condition to a restored condition when the restoring circuit issuitably actuated.

Each of the operating circuits 0C includes a magnetic element M in theform of a core composed of a material having appreciable magneticretentivity, which serves to prepare the operating circuit for operationat the time that the associated pentode P is restored. By virtue of itsmagnetic retentivity each of the magnetic elements M also serves toremember whether the section in which it is located was last restored oroperated, as the case may be. This feature is particularly useful if thecounting circuit is de-energized for any reason. In such a case, byvirtue of the memory function of these magnetic elements, it is possibleto recall the previous conditions of the various sections of thecounting circuit after the counting circuit is re-energized, regardlessof the time elapsed since it was tie-energized. Each of the magneticelements M constitutes a core of an operating transformer T providedwith three windings, namely a primary transformer winding W secondarytransformer winding W and a tertiary, or auxiliary, transformer windingW Each of the restoring circuits SC includes a two-winding restoringtransformer T including a magnetic core m upon which are wound a primarywinding p and a secondary winding s.

A first integrating circuit IC, including a first condenser C; and afirst resistor R is connected in each of the operating circuits 0Cacross the secondary winding W; of the corresponding operatingtransformer T A second integrating circuit 10 including a secondcondenser C, and a second resistor R is likewise connected in eachrestoring circuit SC, across the secondary winding s of the restoringtransformer T in this circuit. The two integrating condensers C and C ineach section S and S" of the first stage 10 are connected in seriesbetween the control electrode CG in each of these sections and a firstbiasing conductor BC Similarly the two integrating condensers C and C ineach section 8" and S"" of the second stage 11 are connected in seriesbetween the control electrode CG in each of these sections and a secondbiasing conductor 3C With these arrangements suitable normal biasvoltages are supplied to the control electrodes CG in each of thesections from the corresponding biasing conductor BC or BC: through thesecondary windings W and s and the integrating resistors R and R of bothgrid control circuits in series.

The primary windings W and W," in the two operating circuits 0C and DC"in the first stage 10 are connested in series in the input 12 thereof sothat each of a series of unidirectional current pulses applied to theinput 12 causes the restored section in the first stage to operate. In asimilar manner, the two primary windings W and W of the operatingcircuits OC' and OC"" in the second stage 11 are connected in series inthe input 13 thereof which in turn is connected to the output 14 of thefirst stage 10 so that each of a series of pulses appearing in theoutput of the first stage operates that section in the second stagewhich is restored at the time that such pulse is created.

With the specific arrangement illustrated herein, when each section S ineither stage operates, it serves to restore the companion section inthat stage and, at the same time, prepares the companion section forsubsequent operation by the next pulse applied to that stage.Connections are provided between the anode A in each section ,8 and theprimary winding ,0 in the restoring circuit SC of the companion sectionin the same counter stage to enable each of the sections S in each stageto be restored in response to the operation of the other section in thatsame stage. Likewise connections are provided between the anode A ofeach section S and the auxiliary winding W;, in the operating circuit DCin the companion section of the same stage to enable the operation ofeach section to prepare the other section in the same stage forsubsequent operation.

More particularly, in order to achieve the desired inter-action of thesections, the anode A of the first section S is connected to an anodesupply conductor PVC through the auxiliary winding W in the operatingcircuit OC" and through the primary winding 2 of the restoring circuitSC" in the second section, in series. With this arrangement the secondsection 5' is restored and the operating circuit OC in the secondsection is prepared for operation, whenever a pulse operates the firstsection S. Similarly, the anode A" of the second section S" is connectedto the anode supply conductor PVC through the auxiliary winding W in theoperating circuit C and through the primary winding p of the restoringcircuit SC in the first section S in series. Likewise with thisarrangement the first section S is restored and the operating circuit OCin the first section is prepared, whenever a pulse operates, the secondsection S".

In the case of the second section S", the anode A" is further connectedto the anode supply conductor PVC in series through the windings W and pmentioned and also in series through primary windings W,' and W;" of thetwo operating transformers T and T in the second stage 11 (through thefirst stage output 14 and the second stage input 13), so that wheneverthe second section S operates a pulse appears at the output 14 of thefirst stage 10 and this pulse is applied to the input 13 of the secondstage 11. Such a pulse applied to the second stage serves to operatewhichever section in that stage is at that time in a restored conditionand prepared for operation as previously mentioned.

Also more particularly, the anode A" of the third section 8'' isconnected to the anode supply conductor PVC through the auxiliarywinding W;," in the operating circuit OC" and through the primarywinding p of the restoring circuit SC in the fourth section in series.Also with this arrangement, the fourth section 8" is restored and theoperating circuit OC" in this section is prepared, whenever a pulseoperates the third section 8". Similarly, the anode A" of the fourthsection 5 is connected to the anode supply conductor PVC through theauxiliary winding W;," in the operating circuit OC, and through theprimary Winding p of the restoring circuit SC in the third section 8" inseries. Also, likewise with this arrangement, the third section 8 isrestored and the operating circuit OC' in this section is prepared,whenever a pulse operates the fourth section 8".

If desired, the anode A of the fourth section 8''" may be furtherconnected to the anode supply conductor PVC through the winding W andp'" mentioned, and primary windings W; of operating circuits OC in thethird counting stage (not shown) similar to each of the two countingstages described, and the anode A in the second section of the thirdcounting stage may in turn be similarly connected to the fourth stage,and so on if counts in groups higher than four are desired. With such anextended arrangement, a pulse is created in the output of each stagewhenever the second section of that stage operates and each pulseapplied to the input of each stage operates whichever section in thatstage happens to be in a restored condition and prepared for operationat the time the pulse is applied.

In order to facilitate counting, an indicator preferably in the form ofa glow lamp GL is connected in the first section S of the first stage10, and another indicator of the same type GL" is connected in the thirdsection 5'' in the second stage 11. Each of these indicators glows whenthe pentode P in the corresponding section is conducting to its anode Aand is dark when the corresponding pentode is not conducting. Each glowlamp GL is connected at one end to a reference voltage conductor RVC andat the other end to the screen grid 86 of the pentode P in therespective sections, as more fully explained hereinbelow.

In one method of operating this counter, the first and third sections Sand S are restored and the second and fourth sections 8" and 8"" of thecounter are operated when a count of zero is to be indicated. Thereupon,when a series of pulses is applied to the counter, the first pulsecauses the first section S to operate, and the second section S" torestore, thus causing the first giow lamp GL to light up. When thesecond pulse is applied, it causes the second section S" to reopcrateand the first section S to restore, thus turning olf the first glow lampGL. Also, at the time the second pulse is applied, the operation of thesecond section S causes a pulse to be transmitted to the second stage11, thus operating the third section 8'' and restoring the fourthsection 5, and causing the second glow lamp GL to light up. When a thirdpulse is applied, the first section S again is operated and the secondsection S is restored, thus lighting up the first glow lamp GL again butwithout disturbing the second glow lamp GL. When a fourth pulse isapplied, the second section S" is operated and the first section S isrestored thus turning olf the first glow lamp GL. At the same time theoperation of the second section S", causes a pulse to be transmitted tothe second stage 11 thus operating the fourth section 8, and restoringthe third section 8', and turning off the second glow lamp GL. Thus,with this arrangement, a count of one is indicated when only the firstglow lamp GL is lit, a count of two is indicated when only the secondglow lamp GL is lit, a count of three is indicated when both glow lampsGL and GL are lit, and a count of four or zero is indicated when bothglow lamps are off, and the counting cycle is recommenccd with everyfourth pulse.

Before explaining the detailed operation of the counting circuit, it isdesirable to describe in somewhat more detail various individual partsof the circuit.

Trigger circuit construction Referring first to Fig. 3, there isillustrated one of the pcntodes P together with its associated electrodevoltage supply circuit, including three potential dividing resistors R Rand R connected in series in the order named between the 13+ terminaland a B- terminal. A positive voltage with respect to ground is suppliedto the B+ terminal, and a negative voltage with respect to ground issupplied to the B terminal from a regulated voltage supply. The anode Ais connected directly to the 13+ terminal, the screen grid S6 isconnected to the junction between the first voltage dividing resistor Rand the second resistor R and the suppressor grid G is connected to thejunction between the second voltage dividing resistor R and thirdvoltage dividing resistor R A glow tube GL is connected in series with adecoupling and current limiting resistor r between the screen grid 86and an auxiliary terminal B which operates at a suitable intermediatereference voltage to cause the glow lamp GL to ignite while the pentodeP is conducting and to remain olf while the pentode is not conducting.The 13+ and 8- terminals are connected respectively to the positive andnegative voltage conductors PVC and NVC of Fig. 1, while the terminal Bis connected to the reference voltage conductor RVC of Fig. 1.

A condenser C is connected across the second resistor R and a cathoderesistor R is connected between the cathode K and ground GR in order toaccelerate a change in condition of the tube from its conducting stateto its non-conducting state or vice versa.

Preferably the circuit elements connectcdto the screen grid 86 and thesuppressor grid G including the ramtors R R R and R and the condenser Care enclosed within a grounded electrostatic shield ES. The shieldsaround the circuit elements connected to the screen grid SG andsuppressor grid G in the respective sections S of the counting circuitare not shown in Fig. 1. However, they are the same type as thatiliustraied in Fig. 3. These shields prevent capacitive interaction between the screen grid and suppressor grid circuits of each section withother portions of the counter.

In order to facilitate an understanding of how the circuit of Fig. 3 isrestored and operated by changes in the bias applied to the controlelectrode CG, ccnsider a potentiometer having its positive grounded andhaving a sliding contact 16 thereon which 13 connectcd to the controlelectrode CG. And for convenience, consider the operation of thiscircuit when the circuit elements have the particular circuit constantswith which it was supplied in an actual model of the counter illustratedin Fig. 1. More particularly, the pentodes used were 6SJ7s and the valueof the individual circuit elements used were those indicated in thefollowing table.

R M 50 R M 300 R meg 1.6 R ohms 150 C3 -/L uf- R 1neg 2 Trigger circuitoperation With the circuit elements having the constants indicated andconnected to a potential supply providing the voltages indicated, thiscircuit has two stable conditions depending upon the value of the biasvoltage applied to the control electrode CG. Thus the tube is conducting to the anode after the negative bias on the control grid CG israised to a value greater than about -2.0 v. and is non-conducting tothe anode after the negative bias is lowered to a value less than about--1.0 v. When in either of these conditions, it is found that if thebias voltage of the control grid CG is changed to a value in a rangebetween a low voltage threshold of about -1.0 v. and a high voltagethreshold of about --2.0 v. the condition of the circuit does notchange. Thus, for example, if the pentode P is conducting with about-2.0 v. or more on the control grid CG, and the bias voltage isdecreased to a value between about 2.0 v. and about l.0 v., the pentodestill conducts normally, with very little variation in plate current.However, when the bias is decreased to some value less than about -l.0v., the pentode P suddenly stops conducting, and remains non-conductinguntil at such time the bias is increased to about 2.0 v., or more.However, if the bias is reduced below about 1.0 v. the tube becomesnon-conducting, and remains non conducting even though the bias returnto some higher value less than about 2.0 v. It is to be noted that whilethe pentode P is conducting no increase in the bias voltage has anytriggering effect whatever, and while the pentode is nonconducting nodecrease in bias has any triggering cfiect whatever.

While the pentode P is conducting, the current flowing to the anode is5.0 ma., the voltage at the screen grid is +136 v., the current to thescreen grid is 1.4 ma., and the voltage on the suppressor is 20 v. Whenthe pentode P is non-conducting to the anode A, the voltage on thescreen grid SG is +76 v. and the current thereto is 2.8 ma. and thevoltage on the suppressor grid is 60 v. Thus, it will be noted that whenthe pentode P is conducting, a large potential is impressed upon theglow lamp GL, causing it to glow, and when the pentode isnon-conducting, a low voltage is applied to the glow tube, causing it toremain dark.

It is to be noted that while the bias on the control electrode CGremains within the range specified above, a change in bias voltagecauses very little change in anode current. However, it does cause achange in the cathode current, which change is absorbed primarily by thescreen grid 86. It is this factor which permits the pentode P to operateas a negative trans-conductance tube. Thus for example, While thepentode P is conducting, the anode current remains at 5.0 ma. as thebias is reduccd to l.0 v. As the bias is reduced further, the current tothe screen grid SG increases sufficiently to reduce its voltage and atthe same time to reduce the voltage on the suppressor grid G. As thesuppressor grid G becomes more negative, further current is driven tothe screen grid SG, and these two grids G and SG being tied togetherelectrostatically by the condenser C this quickly drives the anode tocut off. in a similar manner, if the pentode P is non-conducting, then,as the bias on the control electrode CG gradually exceeds -2.0 v., thecurrent to the screen grid SG is reduced, thereby causing its voltage toincrease, and at the same time, the voltage of the suppressor grid G tobecome more positive until the point is reached where these two grids SGand G become sufficiently positive to permit current to pass from thecathode K to the anode A. When this occurs the current to the screengrid is further reduced, and the anode current is quickly driven to itsmaximum value.

From the foregoing discussion, it is readily appreciated that while thepentode P is normally biased in the range between I.() and 2.0 v. andoperating, if a positive pulse is applied to the control electrode CGsufficient to drive the control electrode beyond the low voltagethreshold, the pentode will be restored. In a similar manner, if thepcntode is normally biased in the above range and restored, a negativepulse of sufficient amplitude applied to the control electrode CG willcause the pentode to operate.

The cathode resistor R in the above circuit acts degeneratively tominimize efiects of fluctuations of the threshold voltages that occur asa result of spontaneous changes occurring in the voltage supply, orthermal drifts in cathode emission, etc., and to spread the thresholdvoltages farther apart than they would otherwise be in the absence ofthis resistor. However, because the pentode is capable of operating as anegative transconductance device at the instant of change fromnonconducting to conducting condition, as described hereinabove, then sofar as effects due to changes in cathode voltage are concerned in theirrelationship to control grid voltages, it is clear that at the time thatoperation (i.e., anode conduction) of the pentode is initiated by apulse, any increase of cathode current drives the cathode K morepositive thus increasing the grid-to-cathode voltage and acceleratingthe turning on of the anode current to its full value, due toregenerative action of resistor R Conversely, when restoration of thepentode is initiated by a pulse, the decrease in cathode current causesthe cathode to become less positive, thus decreasing the grid-to-cathodevoltage, and accelerating the cutting off of the how of anode current.Thus in effect, the presence of the cathode resistor R in a tubeoperating in the negative trans-conductance circuit serves as a signalregenerative element so far as triggering signals are concerned so thatit enhances the effect of any signal impressed upon the control grid.

Each of the pentodes P in the counter circuit of Fig. l is operated inthe manner hereinabove described in detail in connection with thedescription of Fig. 3. In practice the control grids CG in the varioussections S of the counter are normally biased through the correspondingbiasing conductors BC, and BC; to about 1.7 v., that is, to a valueintermediate the upper and lower threshold values of the triggeringcircuits which include the pentodes P. Furthermore, the primary windingp inter-connecting the anode A of each section with the restoringcircuit SC of the companion section is so connected that whenever one ofthe sections operates it impresses upon the grid circuit 60 of thecompanion section a positive pulse of such magnitude as to cause thelatter section to restore. Likewise, the primary windings W whichinter-connect the respective operating circuits DC in any stage of thecounter section with a common current source are so connected thatwhenever a unit current pulse is applied to these primary windings, anegative pulse of sufiicient magnitude is applied to the restoredsection in that stage to cause this section to operate.

Transformer construction Referring now to Fig. 4, there is illustratedan arrangement of transformers which is particularly suited for use inthe grid control circuits of the various sections of the counter ofFig. 1. This transformer arrangement includes the three-windingtransformer T and the twowinding transformer T both of circularconfiguration mounted on one side of a circular base 20 and with theiraxes aligned with the axis of the base. On the opposite side of thebase, there are provided eight prongs 21 extending in a directionparallel to the axis of the base, and circumferentially spaced thereon.Also on the same side of the base, there is an axially-projectinglocking member 22 which serves to register the base upon the socket (notshown) into which it is plugged.

The cores M and m of both transformers are ringshaped. Preferably theradial width of the core sections of the three-Winding transformer T issmall compared to the core diameter, so that the magnetization of thecore material in the outer periphery will be about the same as the corematerial at the inner periphery. In practice, the diameter of the coreis preferably about l6", and the radial-width or annular thickness ofthe core is less than about A of the diameter. In an actual threewindingtransformer T used in the counter of Fig. l, the ring core comprises 8laminations of annealed transformer silicon steel stacked to a thicknessof about 0.2". In actual practice, the core m of the two-windingtransformer T has the same diameter and radial-width as the core of thethree-winding transformer T in order to simplify and standardize theconstruction of the entire assembly.

All the windings on the transformers are wound toroidally on therespective cores and are thus linked by flux in said cores, and all ofthe windings and all of the laminations are mutually insulated from eachother.

In a specific example of the three-winding transformer T used in Fig. 1,the primary winding W has 500 turns, the auxiliary winding W has 250turns, and the secondary winding W has 300 turns. The ends of each ofthese windings are connected to different pairs of prongs 21, except forone end of the auxiliary winding W which is connected by a jumper to oneend of the associated primary p of two-winding transformer T Similarly,the primary Winding p of the two-winding transformer is pro vided with225 turns and the secondary winding s with 300 turns, opposite ends ofeach of these windings being likewise connected to different pairs ofprongs 21, with the exception above noted.

It is to be noted particularly that the number of turns in the auxiliarywinding W is half the number of turns in the primary winding W, of thethree-winding transformer T With this arrangement, if equal currentsflow in these two windings in such direction as to establish opposingmagnetizing forces in the core M thereof, the direction of magnetizationof the core is determined by the current flowing in the primary windingW, as long as both windings W and W are energized, and is in theopposite direction and of the same amount when the auxiliary winding Wis energized alone.

In a specific example of the counter of Fig. 1, the values of thecircuit constants of the elements in the integrating circuits connectedto the two transformers in each section are given as follows:

C ..lLf 0.02 R, M 10 c at. 0.005 R ohms 500 The material of which thecore M of the operating transformer T is composed is preferably suchthat it has a high permeability and a high degree of retentivity.Preferably, the core is substantially closed, having no air gap thereinof such length that it tends to increase the reluctance to anysubstantial degree or to present a pronounced demagnetizing force on themagnetic circuit. Preferably, this material is also of such a naturethat it has a maximum permeability at a low value of magctization force.Preferably, a soft ferromagnetic material is used which has apermeability of about 5,000 to 100,000, when the magnetizing force isless than about 1 or 2 oersteds. For convenience the core m of therestoring transformer T is composed of like material and is alsosubstantially closed.

A small paper cylinder 24 is slipped over the two transformers T and Tafter the transformer leads have been soldered to the prongs 21 and thiscylinder is then filled with molten-wax to provide a compact transformerassembly for use in each section of the counter.

Operation of magnet core Considering now, a typical hysteresis loop ofthe ring core M of the three-winding, or operating, transformer Treference is made particularly to Fig. 5 wherein there is represented agraph of such a hysteresis curve 25. In this graph ordinates representmagnetization and abscissae represent magnetization force. When a unitcurrent is applied to the primary winding W, and no current is appliedto the auxiliary winding W the magnetization force and the magnetizationare at their maximum value as indicated by the point 1 on the curve.Thereafter, if a unit current is applied to the auxiliary winding W soas to produce an opposing magnetization force, the magnetization forceis reduced to one half value, while the magnetization is reduced onlyslightly as indicated by the point 2 of the curve. If the core M ismagnetized only by a unit current passing through the primary winding Wand this current is then shut off, the magnetization force reduces tozero, while the magnetization falls off only slightly because of thehigh percentage retentivity of the core, as indicated by point 3 of thecurve. On the other hand, if unit currents are passing through both theprimary and the auxiliary windings W and W so that the magnetizationforce and magnetization are at values represented by point 2, then ifthe current in the primary winding W is shut off, while that in theauxiliary windings W remains, the flux in the core reverses assuming analmost equal value, due to the reversal of the net value of themagnetization force as represented by point 4 of the curve. If, whilethe core is so magnetized, the current in the auxiliary winding W isthen cut off, the magnetization force is reduced to zero, but themagnetization falls off only slightly due to the high degree ofretentivity of the core material, as indicated at point 5. If, however,a unit current is applied to the primary winding W to provide amagnetization force of opposite direction while the auxiliary winding Wis so energized, the magnetization force is reversed and themagnetization is also reversed, assuming a value of about half itsmaximum value as indicated by the point 6. Thereafter, if the unitcurrent in the auxiliary winding W is shut off while the current remainsflowing in the primary winding W the magnetization force is doubled, andthe magnetization is about doubled attaining its maximum value asrepresented by point 1. If on the other hand, the core is magnetized tothe amount indicated by point 5, and then a unit current is applied tothe primary winding W the magnetization in the core reverses and attainsits maximum value as represented by a point very near point 1. It isunderstood of course that magnetization of the core may not alwaysreturn to the same value as one previously attained but at least returnsto one of approximately the same value.

For convenience, an operating core M is considered positively magnetizedif it is magnetized in such a direction that it is prepared foroperating the associated nega* tive trans-conductance pentode P upon theapplication of a unit current; and a core magnetized in the oppositedirection is considered negatively magnetized. Also for convenience amagnetization force is considered as having the same sign as themagnetization which it produces. Furthermore, for convenience, theconditions of the transformer core M corresponding to points i, 2, 3, 4,5, and 6 are hereinbelow referred to as condition 1, condition 2,condition 3, condition 4, condition 5, and condition 6 respectively.

It will be recalled that the voltage induced in the secondary winding ofa transformer is proportional to the rate of change of flux in thetransformer core. It will also be recalled that the voltage generatedacross the condenser of an integrating circuit connected across such asecondary winding is proportional to the time interval of the voltageproduced across that secondary winding. Accordingly, the integratingcircuit 1C connected across any of the secondary windings W cooperatestherewith to produce across the condenser C of the integrating circuit avoltage which is proportional to and in phase with the fiux change whichoccurs in the corresponding transformer core M. This condition appliesso long as the time constant of the integrating circuit 1C is longcompared to the time interval during which the flux change in questionoccurs as is the case with these circuits. Considering the hysteresiscurve 25 represented in Fig. 5, it will be noted that large changes offlux in each core M occur under some of the conditions mentioned aboveand small changes under other conditions, and that some of these changesare in one direction, and some are in the other, according to variouscircumstances including the previous history of the core. Since each ofthese changes of flux occurs rapidly, the corresponding voltage inducedin the secondary winding W of each operating transformer T issubstantially proportional to the flux change in question.

Operation of counter Considering now, the normal functioning of thefirst stage 10 of the counting circuit of Fig. 1 in detail, in the lightof the foregoing detailed explanation regarding the values andcharacteristics of individual circuit elements therein, assume that thefirst and third sections S and S are in a restored condition, and thatthe second and fourth sections S" and 5"" are in an operated conditionin a normal cycle of operation. Under these circumstances no anodecurrent is flowing in the first pentode P, but unit anode current isflowing in the second pentode P". Due to the previous history of thecircuit, the core M" of the three-winding transformer T in the secondsection S" is negatively magnetized to almost its maximum value, thecore being in condition 3, thus in effect remembering the previoushistory of this circuit. On the other hand, the core M in the operatingtransformer T of the first section S is positively magnetized to aconsiderable extent due to the current in the auxiliary winding W thecore being in condition 4 as a result of the previous history of thecircuit.

Thereafter, when a unit current is applied at the input 12 of the firststage 10 and through the two primary windings W and W the magnetizingforce in the first core M is reversed, causing the magnetization in thiscore also to reverse and to change by a large negative value, the corechanging from condition 4 to condition 6. This large change of fiuxinduces in the associated secondary winding W a large negative voltagewhich drives the control electrode CG of the first pentode P to a biasvalue exceeding 2.0 volts, thus rendering this pentode conducting andoperating the first section S. Simultaneously, the change in magnetizingforce in the second core M" causes the magnetization in that core toincrease in the same direction changing from condition 3 towardcondition l. Upon operation of the first section S, however, the currentto the anode A of the first pentode P flows through the auxiliarywinding W of the second operating transformer T reducing the magnetizingforce in the core M" of this transformer to a half value, and thuspreventing the core from becoming magnetized to the maximum degree, butinstead causing it to become magnetized to an intermediate amount incondition 2. During this operation a small negative voltage pulse isgenerated in the secondary winding W of the second operating transformerT due to the combined action of the two currents in the primary and theauxiliary windings W and W thereof; but at the same time the change influx in the primary winding p" of the restoring transformer T generatesa relatively large positive voltage in the secondary winding s" thereofof such a value, that there is a suiiiciently large positive voltagepulse impressed upon the control electrode CG of the second pentode P"as to cut off this pentode and thereby restore the second section S".Thereafter, when the unit current pulse applied to the input 12 isturned off, the magnetization of the second operating core M" isreversed, while plate current continues to flow in the first pentode P,the magnetization of core M" changing to condition 4. At the same time,because the current in the primary winding W, of the first operatingtransformer T is turned off after the current in the auxiliary winding Wthereof is turned off, the magnetization in this core M falls onlyslightly, the magnetization of this core attaining condition 3.

At this time the magnetization condition of the two cores M and M areinterchanged from those initially assumed. Accordingly the secondoperating circuit is now prepared to be operated when the next pulse isapplied to the input.

At the same time that the current to the anode A of pentode P is cut oilas above described, a large positive pulse is generated in the secondarywinding W in the third section 8 but this voltage has no effect sincethe pentode P'" in this section is already restored. Subsequently, whenthe next pulse is applied to the input 12 of the first stage It], thereversal of magnetization in the second core M" causes the secondsection S" to operate and the operation of this section causes the firstsection S to restore in the manner hereinabove described, the operationof the two sections being entirely symmetrical. When the second section5'' operates, it causes a unit current to flow in the third operatingprimary winding W causing a large flux reversal and operating the thirdsection, which, in operating, causes section 8"" to restore.

It is to be noted that each time the first and third sections S and S'operate, the glow lamps GL' and GL associated therewith glow, so thatthe accumulative count in a counter is indicated.

A condenser C shunts the primary windings W and W of the first andsecond operating transformers T and T and another condenser C shunts thewindings W and W of the third and fourth operating transformers 1' and Tin order to prevent high frequency components of current changes throughthe respective primary windings from capacitively inducing such largevoltages in the grid control circuits GC as to affect their action.Preferably these by-pass condensers C and C tune the primary windings W,to a fre quency which is high compared to the frequency of pulses to becounted. However, the Q's of the respective parallel networks includingthese condensers C and C and the corresponding transformer primaries aredesigned to be sufficiently low to prevent these networks fromoscillating when pulse currents are applied thereto or removedtherefrom; that is, each of these parallel networks is more thancritically damped. If desired, separate tuning condensers may beconnected across the individual primary windings. Suitable values forthese bypass condensers are: C =0.005 ,uf., and C =0.0O5 f.

Memory function In order to illustrate the memory and recall function ofthe operating cores, consider, by way of example, a case in which thecounter is indicating a count of two. Under these circumstances, thesecond counter section S" and the third counter section 8" are in theiroperated condition and the first counter section S and the fourthcounter section 5''" are in their restored condition. Under thesecircumstances, the count of two is indicated by the fact that the firstglow lamp GL' is dark and the second glow lamp GL is bright.

Under these conditions, a unit current is flowing to the anode A" of thesecond pentode P" through the auxiliary winding W of the first operatingtransformer T and the primary winding p of the first restoringtransformer T and through the primary windings W and W of the third andfourth operating transformers T;"' and T{''. Also a unit current isflowing to the anode A' of the third pentode P through the auxiliarywinding W of the fourth operating transformer T and through the primarywinding p" of the fourth restoring transformer T It is clear that underthese conditions, because of the various currents flowing in theoperating transformers T the first, second, third and fourth operatingcores M are respectively magnetized in conditions 4, 3, 1, and 2.

To de-energize the counter in such a way that it will be conditioned torecall the count of two, the various elements of the counter arede-energized in a predetermined sequence. In this de-energizationprocess the respective operating cores M become magnetically polarizedin specific directions corresponding to that count. Subsequently theelements of the counter are re-energized in a particular sequence inorder to prepare the counter for recalling the count. Then a series ofpulses equal in number to the maximum number indicated by the counter(in this case, four) are applied to the counter to recall and indicatethe prior count of two.

More particularly, in de-energizing the counter, the first step is tode-energize the control grids CG in each counter stage in the order inwhich the stages are interconnected; that is, the control grids CG ofthe first stage 10 are de-energized before those in the second stage 11,and so on, if there are more than two stages. This sequence is followedin order to assure restoring the second or output section of each stagebefore de-energizing any following stage. The de-energization of thecontrol grids in any stage effectively de-energizes the sections in thatstage provided that precautions are taken to prevent these sections fromoperating momentarily when the other electrodes in those sections arede-energized. If this procedure is not followed, the operating cores ofthe following stages may not be properly polarized to remember the lastcondition of the sections in that stage.

The next step is to de-energize the anodes A of the various pentodes P.All of the anodes A may be defourth core M"" energized simultaneously ifdesired, it only being important that the anodes in the respectivestages are deenergized subsequently to the control grids CG in order toprevent spurious pulses from being created in the respective sections Sby the multiple vibrator action that may otherwise occur. The next stepin the de-energization process, is to de-energize the auxiliary grids SGand G, it being important that they be de-energized after the anodes inorder to preclude any momentary conduction of the pentodes P that mightotherwise occur. Thereafter, to complete the de-energization of theentire counter circuits, the heaters H associated with the respectivecathodes K are deenergized.

In de-energizing the counter, the first biasing conductor BC the secondbiasing conductor BC and the anode supply conductor PVC, are grounded inthe sequence mentioned, and then the negative voltage conductor NVC andthe reference voltage conductor RVC are grounded together or in anysequence.

When the first biasing conductor BC is grounded, in effect a positivepulse is applied to each of the control electrodes CG and CG in thefirst stage 10. The application of a positive pulse to the secondpentode P" renders it non-conductive. As a result, a negative pulse isinduced in the control circuit GC' of the first section S but this pulseadded to the positive pulse simultaneously applied to the controlelectrode CG in the first section S is insuflicient to cause thissection to operate. As a result the magnetization of the first operatingcore M changes from the condition 4 to condition 5. At the same time nochange occurs in the second operating core M", it remaining in condition3. Both pentodes P and P" in the first stage 10 are now non-conductiveand the two corresponding sections S and S" are restored.

At the same time that the second section S" restores, the unit currentpreviously passing through the primary windings W and W," of the thirdand fourth operating transformers T and 1' is terminated. When thiscurrent terminates, the magnetization of the third operating core M'changes from condition 1 to condition 3. As a result a small positivepulse is impressed upon the control electrode CG of the third pentode P,this positive pulse being insufficient to restore the third section 8'.Also at the time that the current in the second pentode terminates themagnetization of the is reversed, changing from condition 2 to condition4, by virtue of the continuation of the flow of current to the anode A'of the third pentode P. As a result, a large positive pulse is impressedupon the control electrode CG"" of the fourth pentode P"" but this pulsehas no effect since the fourth pentode P' is already restored.

When the second biasing conductor RC is grounded, in effect, a positivepulse is applied to both the third and fourth control electrodes CG'"and CG"". The positive pulse applied to the third control electrode Ccauses the third pentode P' to restore, terminating the current to itsanode A and, as a result, generating a negative pulse in the controlcircuit GC"" of the fourth pentode P". However, the net voltageimpressed upon the fourth control electrode CG'' as a result of theconcurrent application of this negative pulse and the positive pulsecreated by the termination of the current in the primary winding Wf'" ofthe fourth operating transformer T does not become sufficiently negative at any time to render the fourth pentode P"" conducting. As aresult there is no change in the magnetizing force in the thirdoperating core M' and it remains negatively magnetized in condition 3.On the other hand, when the current flowing to the third pentode Pthrough the auxiliary winding W of the fourth operating transformer Tterminates, the magnetization condition of the fourth operating core M""changes from the condition 4 to condition 5.

After the two biasing conductors BC and BC: have been grounded, theanode supply conductor PVC and the negative voltage supply conductor NVCand the reference voltage supply conductor RVC are grounded and theheaters H de-energized in the manner previously explained, this portionof the de-energization process having no effect upon the magnetizationof the operating cores M.

It is to be noted that after all of the control electrodes CG have beenthus grounded, the operating cores M" and M" in the second and thirdsections S" and S" are negatively polarized; and the operating cores Mand M" in the first and fourth sections S and 8" are positivelypolarized. in general, regardless of the particular count previouslyindicated by the counter just prior to the grounding of the controlelectrodes CG in the manner explained, the operating cores M of thosecircuits which were last operating are negatively polarized and those inthe sections which were last restored are positively polarized. In thisway, a count image in the form of a magnetization pattern or picture isimpressed upon the set of operating cores which corresponds uniquely tothe last indicated count. Thus by this de-energization process thecounter circuit is conditioned to facilitate the recall of the priorcount provided the counter is suitably re-energized by virtue of thecreation of a permanent magnetization pattern of that count. Thispattern is used to control the recall of the last indicated countwhenever desired.

Recall function In order to reenergize the counter preparatory torecalling the last prior count, the heaters H associated with thecathodes K are first energized and the cathodes heated to their normaloperating temperatures. Then the negative voltage conductor NVC isenergized. Then the anode voltage conductor PVC and the auxiliaryvoltage conductor RVC are energized together, the energization of theanode voltage conductor PVC preferably being gradual in order to preventany voltage shock to the circuit which might accidentally operate one ormore of the pentodes P. The rate at which the anode voltage is raised toits full value should be slow enough to permit the voltage on thecondenser C connected between the screen grid SG and the suppressor G ofeach pentode P to maintain the suppressor sufficiently negative relativeto the screen to prevent the pentode P from conducting to its anode A.Next, the biasing conductors RC and BC are energized to their normalnegative voltages, it being immaterial in which order the biasingconductors are energized, since all of the pentodes P are non-conductingat the time. While it would be possible to energize the biasingconductors before energizing the anode voltage conductor PVC, theprocedure described is preferred, since it permits the screen andsuppressor grids SG and G to be energized to their maximum negativevoltages at the time that positive voltage is applied to the anodes A,thus preventing accidental operation of any pentodes P. It is to benoted that this re-energization process is performed without operaatingany counter section S and without disturbing the magnetization patternof the count image previously impressed upon the set of cores M. Withthe counter thus re-energized in this manner, the circuit is prepared torecall the last previous count.

in order to recall the last prior count, four pulses of unit current areapplied to the input 12 of the first counter stage 10. For example, whena last prior count of two is to be recalled, then when the first pulseis initiated, the magnetization of the first core M is reversed from thepositive value of condition to the negative value of condition 1. Thisreversal of magnetization generates a large negative pulse which isimpressed upon the control electrode CG of the first pentode P making itoperate. Upon operation of the first pentode P, the resultant anodecurrent flowing through the auxiliary winding W," of the secondoperating transformer T in cooperation with the unit pulse applied tothe primary winding W thereof, changes the magnetization of this corefrom condition 3 to condition 2 in the manner previously explained. Upontermination of the first unit pulse, the magnetization of the first coreM changes from condition 1 to condition 3. The small resultant positivevoltage impressed upon the first control electrode CG is insufficient torestore the first pentode P. Also at the time of termination of thefirst pulse, the magnetizing force in the second operating core M isreversed, changing from condition 2 to condition 4. The resultant largepositive pulse impressed upon the second control electrode CG has noeffect, since the second pentode P is already restored. Because thefirst pentode P' is conducting, the first glow tube GL' shines.

When the second pulse is applied, the magnetization in the second core Mreverses, changing from condition 4 to condition 6. The resultant largenegative pulse impressed upon the second control electrode CG" causesthe second pentode P" to operate. Upon operation of the second pentodeP, the resultant current flowing to its anode A causes a large positivepulse to be impressed upon the first control electrode CG' through thefirst restoring transformer T thereby restoring the first pentode P. Thetermination of the current to the anode A of the first pentode P causesan increase in the magnetization in the second operating core M" fromcondition 6 to condition 1. The resultant small negative voltageimpressed upon the second control electrode CG" is ineffective, sincethe second pentode P is already conducting. Also at the same time thatthe first pentode P is restored, the first glow tube GL' darkens.

As a result of the application of the second pulse and the operation ofthe second pentode P, the magnetization of the first core M changes fromcondition 3 to condition 2 in accordance with the principles hereinaboveexplained. Also as a result of operating the second pentode P", a unitpulse is initiated through the primary windings W and W;" of both thethird and fourth operating transformers T and T The application of thisunit pulse causes the polarity of the fourth operating core M" toreverse, the magnetization of this core changing from condition 5 tocondition 1. The large resultant negative voltage impressed on thefourth control electrode CG" renders the fourth pentode P" conducting.

By the combined action of the current flowing in the anode A of thefourth pentode through the auxiliary winding W;,' of the third operatingtransformer T the magnetization of the third operating core M" changesfrom condition 3 to condition 2. Termination of the second pulse causesthe magnetization of the first core M to reverse, changing fromcondition 2 to condition 4. The third pentode P'" remains restored andthe fourth pentode P" remains operated in accordance with the principlesset forth above.

When the third pulse is applied, the first section S operates and thesecond section S restores, causing the first glow tube GL' to shineagain and terminating the unit current previously applied to the secondstage 11. When this unit current terminates, the magnetization of thethird operating core M changes from condition 2 to condition 4, and themagnetization of the fourth operating core M" changes from condition 1to condition 3, the third section remaining restored and the fourthsection remaining operated. After the third pulse has terminated thefirst and fourth operating cores M and M are negatively polarized incondition 3, and the second and third operating cores M and M'" arepositively magnetized in condition 4.

When the fourth pulse is impressed upon the input of the first stage,the first section S restores, darkening the first glow tube GL, and thesecond section 8'' operates, initiating a new unit pulse at the input 13of the second stage 11. The initiation of the latter pulse causes thethird section to operate, thereby lighting up the second glow tube GL"and also causes the fourth section 8"" to restore.

From the foregoing explanation, it is seen that when the fourth pulsehas been applied, each of the sections S of the counter is in the samecondition, that is operated or restored, that it was in prior to thede-energization of the entire counter. Thus by de-energizing andre-energizing the counter and then applying a series of pulses theretoin the manner described, it is possible to remember the count lastindicated by the counter prior to its de-energization for an indefiniteperiod and to recall that count.

Zeroing procedure Not only may a count of this circuit be remembered andrecalled, but, if desired, any count may be erased and the counterzeroed. In zeroing the counter of Fig. 1, consider, for example, astarting condition in which the counter indicates a count of 2. In thiscondition, the first and fourth sections S and 8"" are restored and thesecond and third sections S" and S" are operating; and the first glowlamp GL' is dark and the second glow lamp GL" shines. While in thiscondition the first, second, third, and fourth operating cores are inconditions 4, 3, l, and 2 respectively.

In the zeroing process a unit current pulse is applied to the input 12of the first stage 10, operating the first section and restoring thesecond section. Then, while this pulse is still applied, the controlelectrodes CG and CG'" of the first and third sections S and S aregrounded, restoring both of these sections; and then, the controlelectrodes CG" and CG"" of the second and fourth sections S" and S"" arebiased very negatively to operate these sections. Then the negative biason the control electrodes CG" and CG"" is reduced to a normal negativebias of about l.70 volts, leaving the second and fourth sections S" and8"" operated. The grounded control electrode CG and CG" are thenungrounded and the bias on these electrodes is raised to a normalnegative basis of about l.70 volts, leaving the first and third sectionsS and S'" restored. The unit pulse current applied to the input 12 ofthe first stage 10 is then terminated. At the completion of thisprocess, the first and third sections S and S'" of the counter arerestored, the second and fourth sections S" and S"" are operating, thetwo glow lamps GL' and GL" are dark, and the counter is prepared tocount pulses.

At the time that the unit pulse is applied to the input 12 of the firststage 10, the first core M changes from condition 4 to condition 6,operating the first section S. The first section S, in operating, causesthe second section S" to restore, as previously described, and themagnetization of the second core M" changes from condition 3 tocondition 2. When the second section S" restores the magnetization ofthe first core M changes from condition 6 to condition 1 and themagnetization of the third core M' changes from condition 1 to condition3 and that of the fourth core M"" from condition 2 to condition 4.Thereafter, when the control electrodes CG and CG' in the first andthird sections S and S'" are grounded, restoring the pentodes P and P'in these sections, the first core M remains in condition 1 but themagnetization of the second core M" changes from condition 2 tocondition 1, the third core M" remains in condition 3, and themagnetization of the fourth core M"" changes from condition 4 tocondition 5. Then at the time that very negative bias is applied to thecontrol electrodes CG" and CG"" of the second and fourth pentodes P" andP"" resulting in operation of these tubes, the magnetization of thefirst operating core M changes from condition 1 to condition 2 while thesecond operatiug core M" remains in condition 1, that of the thirdoperating core M'" changes from condition 3 to condition 2 and that ofthe fourth operating core M"" from condition 5 to condition I. When thebiases on all the control electrodes CG are returned to their normalvalues, no change occurs in the magnetization of the cores M. However,when the current pulse is terminated, the magnetization of the firstcore M changes from condition 2 to condition 4 and that of the secondcore M" from condition l to condition 3.

It is to be noted that at this time, only the first operating core M ispositively magnetized, being in condition 4, while the second, third andfourth cores are negatively magnetized, being in conditions 3, 2 and 1respectively. With the pentodes in the conditions mentioned and thecores so polarized, the counter is ready to count pulses. If any otherstages are cascaded in the counter and are similarly treated, the firstsections of these stages are likewise restored and the last or outputsections operated after the completion of the zeroing process and theoperating cores in the first sections and those in the output sectionsof all stages following the first will be in conditions 2 and 1respectively. While the zeroing process has been described withparticular reference to zeroing the counter when a count of 2 isindicated, it is to be understood that the various sections of thecounter are in the same final condition and the counter is prepared forcounting pulses, at the completion of the zeroing procedure describedirrespective of the initial conditions of the various sections of thecounter, the only difference being in the specific history of the coresduring the procedure.

Auxiliary circuits As illustrated in Fig. 2 certain auxiliary circuitsare provided to ensure reliable operation of the counter. These circuitsinclude a pulse standardizer 30 for applying pulses to be counted to theinput 12 of the first stage 10 of the counter, a zeroing circuit 32 forzeroing the counter, a control circuit 34 for automatically energizingand deenergizing the various electrodes of the counter and the pulsestandardizer 30 in the desired sequence in order to remember and arecall a count, and a pulsing circuit 36 for applying a series ofrecalling pulses to the counter.

Pulse standardizer The pulse standardizer 30 is in the form of a directcoupled D.C. amplifier comprising first, second, and third pentodes P Pand P connected in tandem amplifying relation between the input 38 andthe output 40. The potentials for the various electrodes of these threepentodes are obtained from a voltage dividing circuit 42 includingresistors R R R R R and R one end of which is connected to ground andthe other end of which is connected to the negative voltage conductorNVC.

Negative pulses to be counted are applied to the first pentode P througha coupling condenser C. and a potentiometer 44. This pentode P isnormally conducting and is driven beyond cut off by negative pulsesexceeding a predetermined value determined by resistor R The anode 46 ofthe first pentode P is directly connected to the control grid 48 of thesecond pentode P and the two connected to the potential dividing network42 through a first plate resistor R This resistor R cooperates with thevoltage of the voltage dividing network 42 to bias the second pentode Pbeyond cut off as long as the first pentode P is conducting and torender the second pentode P conducting in a predetermined amount whenthe first pentode P is driven beyond cut off.

The anode 50 of the second pentode P. is directly connected to thecontrol electrode 52 of the third pentode P and the two pentodes areconnected to the potential dividing network 42 through a second plateresistor R The third pentode P is connected as a negativetransconductance device in a manner similar to the pentodes Him! 19 P ofthe counter circuit. The second plate resistor R1 and the potentialdividing network 42 cooperate to maintain the third pentode Pnon-conductive while the sec ond pentode P is not conducting, butmaintains the third pentode P conducting when the second pentode P isconducting.

With this pulse standardizer 30, whenever a negative pulse having anamplitude exceeding a predetermined value is impressed upon the input38, a unit pulse of the same magnitude of those generated in varioussections of the counter is produced at the output 40.

The screen grid 53, the suppressor grid 54, and the anode 55 of thethird pentode P are energized through a voltage dividing circuitcomprising resistors R R and R similarly to the pentodes P of thecounter circuits and a glow tube GL is connected to the screen grid 53of this pentode also in a similar manner. This glow tube GL serves toindicate when pulses are being generated in the output of the pulsestandardizcr 30, and is particularly useful in connection with theadjustment of the potentiometer 44 at the input 38 to a suitable settingfor picking up all the pulses of interest in the source of the pulses tobe counted. During any such adjustments the third pentode P is connecteddirectly to the anode voltage conductor PVC by means of single poledouble-throw switch 56. However, when pulse counting is desired thepentode is connected through output 40 directly to the input 12 of thefirst stage of the counter by means of this switch.

The plate resistors R and R are preferably very large compared to theresistors R to R in the voltage divider 42 so that changes in platecurrent will not substantially aflect the distribution of voltage on thevoltage divider.

In de-energizi-ng ot the entire arrangement, the control grid'52 of thethird-pentode P7 is grounded before the control grids CG in the counter,in order to be certain that any unit current generated by the pulsestandardizer and impressed upon the first stage 10 of the counter isterminated before the biasing conductors BC and BC, are grounded. Also,in re-energizing the pulse standardizer, the control electrode 52remains grounded until after the other electrodes of this pentode P havebeen energized to prevent applying a spurious pulse to the counter.

Suitable values of the circuit constants in the pulse standardizer 30are as follows:

1 .'Y. 7 -7 T R "ohms-.. 300 R M 5 R "ohms-.. 350 R M 4.7 R1: OhmS R M25 R M 25 The pentodes used in this circuit are 6SJ7s.

Pulsing circuit grid 57. Suitable values of these resistors are: R15mcg-.. 1 R M 180 The switching means referred to includes a normallyopen push-button switch 60 which may be depressed momentarily tocomplete the circuit between the voltage divider 58 and the suppressorgrid 57 once to produce a single pulse at the output of the pulsestandardizer. The switching means also include a rotary switch 62adapted to complete the circuit between the voltage divider 58 and thesuppressor grid 57 a predetermined number of times in a singleoperation, so as to apply to the counter the proper number of pulses, inthis case four, necessary to recall a prior count.

The rotary switch 62 comprises a metallic wheel 63 connected to theintermediate point of voltage divider 58, carrying an insulated lever 64which is normally held against a first stop 65 by means of an insulatedspring 66, and which may be moved to a second position against a secondstop 67 by manually applying pressure to the lever 64 against the forceof the spring 66. The wheel 63 carries a plurality of metallic teeth 68,in this case two, which contact a resilient switch element 69 once eachin the movement of the wheel 63 from the first position to the secondposition and once each again with the movement of the wheel from thesecond position to the first. Upon making each contact, the circuit tothe suppressor grid 57 is completed to produce the desired pulse. Acondenser C connected across the cotary switch 62 and aross thepush-button switch 60 serves to prevent sparking when either of theswitches referred to is operated. A suitable value of the condenser is:C =0.005 at.

The suppressor of the first pentode P is connected to the voltagedivider 42 of the pulse standardizer through a parallel networkincluding a resistor r and a condenser C; which has a time constantwhich is long compared to the period of any chattering that might occurupon the closing and opening of the contacts of the pulsing circuit butwhich is less than the interval between the successive closing ofdifferent contacts of the rotary switch 6!. Suitable values of thesecircuit elements are:

r M.... 27 C "at" 0.1

Zeroing circuit The zeroing circuit 32 serves to restore the first andthird sections S and S' and to operate the second and fourth sections Sand 8''" so as to prepare the counter properly for counting pulseshereinabove explained. In order to bring about the zeroing of thecounter automatically, the zeroing circuit is provided with threeswitches,- namely, a pulsing switch 74, a grounding switch 75, and abiasing switch 76, which are ganged to close in the order named and thento open in the reverse order to bring about the desired results.

The pulsing switch 74 is arranged in parallel with the push-buttonswitch 60 of the pulsing circuit 36 so that when this switch 74 isclosed, it serves to generate a pulse in the output of the pulsestandardizer 30.

The grounding switch 75 is arranged to ground the control grids CG andCG' of the first and third pentodes P and P'" through two mutuallyinsulated grounding conductors BC The first grounding conductor BC, isconnected to the junction between the two condensers C and C in the gridcircuit GC of the first pentode P, and the second grounding conductor BCis similarly connected to the junction between the condensers C and C inthe grid circuit GC" of the third pentode P'".

The biasing switch 76 cooperates with a voltage divider 78 and twocoupling circuits 80, to maintain a normal bias of about 1.7 volts onthe two biasing conductors BC; and BC: while this switch is open and toraise the bias above about 2.0 volts when this switch is closed. Thevoltage divider 78 includes two resistors R and R connected between thenegative voltage conductor NVC and ground. The junction between thesetwo resistors R and R is connected to the respective biasing conductorsBC, and 30 through two resistors R1. in-

the respective coupling networks 80. The two condensers C, in therespective coupling networks 80 are connected directly across therespective biasing conductors BC; and BC, and ground so as to prevent anelectrostatic pickup in the two grounding conductors BC, and BC, fromactu ating any section of the counter. Preferably these two condensersC, are located adjacent the grid circuits GC. The two coupling networks80 serve to isolate the two bias conductors BC and BC, from each otherelectrically and the constants of these circuits are so close that thegrounding of the first biasing conductor BC does not produce anysubstantial voltage change on the second biasing conductor BC Anauxiliary resistor R is included in series with switch 76 so as to shuntthe high voltage resistor R of the voltage divider 78 when the switch 76is closed. The shunting of this resistor R raises the voltage of thejunction between the resistors R and R so as to bias the control gridsCG" and CG"" in the second and fourth sections S" and S"" to the desiredpoint.

Suitable values of the circuit elements referred to are as follows:

When these three switches 74, 75, and 76 are closed the first and thirdoperating cores M and M'" are magnetized in condition 2 and the secondand fourth operating cores M" and M"" are magnetized in condition 1.Thereafter opening of the pulsing switch 74 terminates the currentthrough the primary windings W and W of the first and second operatingtransformer T and T causing the magnetization of the first core M tochange from condition 2 to condition 4 and that of the second core M" tochange from condition 1 to condition 3, as described above under ZeroingProcedure. Opening of the grounding switch 75 and the biasing switch 76have no effect on the magnetization of the cores.

While the opening and closing of the three switches 74, 75, and 76 havebeen described with reference to a particular sequence, it will beclear, in view of the foregoing explanation of the invention, that theseswitches may be opened and closed in other sequences to zero thecounter, it only being important that the input sections S and S' arerestored and the output sections S" and 8"" be operating at the timethat the current pulse applied by the pulse standardizer 30 to thecounter is terminated.

Power supply The power supply 81 for energizing the counter and theassociated circuits is of the type which converts alternating currentpower into direct current power. This power supply 81 comprises a pairof input terminals 82 to which alternating current voltage is appliedthrough a power switch 84 and two output terminals 85 and 86 at whichthe respective 13+ and B- voltages of suitable values appear, and alsotwo output terminals 87 at which low voltage cathode heater voltageappears. The power supply 81 is also provided with a terminal 88 whichis grounded at a voltage between that of the B+ and the 3- terminal.This power supply may be of any conventional type in which precautionsare taken to prevent the appearance of voltages at the 8+ and B-terminals, until the cathodes K of the various pentodes P energized fromthe heater terminals 87 have reached their normal operating temperature.

The heaters H of the various pentodes in the circuits described areenergized directly from the heater terminals 87 so that the cathodes maybe rendered thermal- 1y emissive or not according to whether the powerswitch 84 is closed or open. The voltages from the 3+ and the terminals85 and 86 are applied to the various por- Control circuit The firstrelay L is of the slow-torestore type and has first and second pairs ofcontacts X and X the two pairs being arranged to act in the order namedwhen the relay operates and in the inverse order when it restores. Thefirst pair of contacts X is normally open and in a line between the Bterminal 86 and the negative voltage conductor NVC. The second pair ofcontacts X, is normally closed and when closed completes a groundingcircuit between the connected ends of the solenoids Y and Y, of thefirst and second relays L and the connection to the latter relay onlybeing made through a resistor R connected between these solenoids.

The second relay L is also of the slow-to-restore type but restores morerapidly than the first relay L and is provided with first, second andthird pairs of contacts, X X and X the three pairs acting in the ordernamed when the relay operates and in the inverse order when it restores.The first pair of contacts X is normally closed to complete a circuitincluding a grounded resistor R on one side thereof and a filter network89 including a resistor R and a condenser C on the other side thereof.This resistance-capacitance network 89 is connected between that side ofthis pair of contacts X and a voltage divider 89' including tworesistors R and R which supplies suitable voltages to the anode voltageconductor PVC and to the reference voltage conductor RVC. The secondpair of contacts X is normally opened and is included in a circuitbetween this resistance capacitance network 89 and the B+ terminal ofpower supply 81. The third pair of contacts X is normally open and isincluded in a line 90 which includes the solenoid Y; of the third relayL and a normally closed off switch 91. This line 90 is connected on theload side of the main power switch 84.

The third relay L is of the fast-to-restore type and is provided withfour pairs of contacts X X X and X the first and second and third pairsbeing normally closed and the fourth normally open, and the four pairs'being arranged to act in the order named when the third relay operatesand in the inverse order when restored. The first and second pairs ofcontacts X and X are arranged between ground and the second and firstbiasing conductors BC, and BC, respectively. The third pair of contactsX is arranged in a line including a small current limiting resistor rbetween ground and an intermediate point on the potential divider 42 atthe cathode 93 and ground serves to prevent shock to the volt- 30. Alarge condenser C connected between the cathodes 93 and ground serves toprevent shock to the voltage divider 42 when the contacts X, are openedand closed. Suitable values for the last two circuit elements mentionedare:

r 0hms C 2 .Hf 8.0

The fourth pair of contacts X is arranged in parallel with a normallyopen on switch 95 which is connected in series with a resistor R betweenthe B+ terminal 85 and one end of the solenoid Y; of the first relay L1.

The upper end of the voltage divider 89' is connected directly to theanode voltage conductor PVC and an intermediate point between theresistors R and R is connected to the reference voltage conductor RVC.The resistor R at the lower end of the voltage divider 89' is shunted bya condenser C which serves to ground the reference voltage conductor RVCso far as pulse frequencies are concerned and thus isolates the glowlamps GI. from each other so that a pulse applied to one will notinadvertently ignite another. In the preferred form of the invention,the time constant of the resistance-capacitance network 89 through whichthe potential divider 89 is supplied is longer than the time constant ofthe resistance-capacitance networks including the resistors R and Cconnected between the screen grids and the suppressor grids of therespective pentodes P in the counter and the output pentode P in thepulse standardizer. With this time constant so selected, as the anodevoltage rises to its ultimate value during the energization of thevarious circuits, the voltage at the suppressor grids does not rise sofast as to cause anode conduction. This facilitates maintaining alltubes in a restored condition during circuit energization.

Suitable values of the circuit elements associated with the two voltageconductors PVC and RVC are:

Energization of circuit To energize the circuit, first the main switch84 is closed causing the heaters H associated with the various cathodesof the pentodes P to be energized. Subsequently, after the voltages atthe B+ and the B terminals 85 and 86 have attained their normaloperating values, the energization of the remaining electrodes of thevarious circuits is initiated by temporarily depressing the on button95, operating the first relay L and holding it closed until the stickingcontacts X of the third relay L close to seal in the control circuit 34.Upon operation of the first relay L as its first pair of contacts Xcloses, thereby energizing the negative voltage conductor NVC andimpressing negative voltages upon the screen grids and the suppressorgrids of all the negative trans-conductance pentodes P, P", P'", P"" andP and at the same time placing a suitable negative voltage across thepotential divider 42 in the pulse standardizer 30. It is to be notedthat this voltage divider 42 does not come into full operation becausethe intermediate point thereon is .still grounded through resistor r andthe third pair of contacts X, of the third relay L Also at the time thatthe negative voltage conductor NVC is energized, the voltage dividers S8and 78 in the pulsing and zeroing circuits 36 and 32 are energized.However, the energization of the latter voltage dividers SS'and 78 doesnot have any effect upon the counter at this time, since the biasingconductors BC; and BC: are still grounded through the first and secondpairs of the contacts X and X of the third relay 1 After the negativevoltage conductor NVC is energized, the second pair of contacts X of thefirst relay L opens, thereby connecting the solenoid Y of the secondrelay L to the 13+ terminal 85 through the resistor R the solenoid Y, ofthe first relay L the on button 95 and the resistor R thereby operatingthe second relay. When the second relay L operates, its first pair ofcontacts X opens and its second pair of contacts X closes, therebyungrounding the resistance capacitor network 89 and connecting thisnetwork to the 13+ terminal 85. When this occurs, the full voltage fromthe 3-!- terminal 85 is applied gradually through theresistance-capacitance network 89 to the anode voltage conductor PVC andthe potential divider 89'. The time constant of this network 89 ismadesufficiently long compared to that of the cirwits-including thecondensers C connected between the respective screen and suppressorgrids that accidental operation of the negative transcnnductanccpentodes P, P", P'", P"" and P is prevented. The vo'tage on thereference conductor RVC rises to its normal value concurrently but moreslowly. Preferably the time constants of'theccircuits asspciatedwiththese two conductors PVC 24 and RVC are so selected with reference tothe constants of the voltage divider network 89 that the glow lamps GLdo not flash even momentarily during the energization process. In anyevent, accidental operation of the pentodes P, P", P', P"" and P isprevented so long as the following relationship holds:

After the main voltage divider 89' has been energized, the third pair ofcontacts X of the recond relay L closes, thereby completing the powercircuit to the solenoid Y;, of the third relay L and operating thisrelay.

When relay L operates, the first two pairs of contacts X and X open,thereby ungrounding the bias conductors BC and BC, and permitting theirvoltages to attain their normal values as established by the voltagedivider 78 in the zeroing circuit 32. Subsequently the third pair ofcontacts X open, ungrounding the intermediate point of the potentialdivider 42 in the pulse standardizer 30 and permitting this voltagedivider to attain its normal voltage distribution, rendering the firstpentode P therein conducting and leaving the second and third pentodes Pand P therein non-conducting. Subsequently, the fourth pair of contactsX close, scaling in the first relay L and hence the entire controlcircuit 34 so that all three relays L L and L remain operated eventhough the on" button subsequently released.

After all three relays L L and L have operated in the manner describedand the control circuit 34 is sealed in, the pulse standardizer 30 isready to operate and the counter circuit is prepared to receive pulsestherefrom, whether it be for the initial operation of the counter orwhether it be to recall a prior condition thereof. or whether it be tozero the counter as above described, or for some other purpose.

De-energization of circuits In order to tie-energize the counter and thepulse standardizer automatically, the normally closed off" button 91 isdepressed, thereby de-energizing the solenoid Y of the third relay Lcausing this reiay to restore. When this relay L restores, the fourthpair X of contacts opens, thereby de-energizing the first and secondrelays L and L The third pair of contacts X thereupon close, groundingthe intermediate point of the voltage divider 42 of the pulsestandardizer 30. This grounding procedure impresses a positive pulse inthe control grid 52 of the output pentode P thereby rendering itnon-conducting in the event that it is already conducting andterminating any unit current that might then be flowing in its output40, for the reasons hereinabove explained. Thereupon the second pair ofcontacts X1 close, grounding the first biasing conductor BC, andrestoring any section 5' or S" of the first stage 10 of the counterwhich is operating at the time. Subsequently, the first pair of contactsX closes, grounding the second biasing conductor BC; and restoring anysection 8' or 5"" of the second stage 11 of the counter which isoperating at the time.

The time required for the first and second relays L and L to restoreexceeds the time required for the four pairs of contacts X X- X and X ofthe third relay L to restore. Accordingly, after the restoration of thethird relay L is complete, the second relay L restores, its third pairof contactsX opening first, thereby breaking the circuit to the solenoidY of the third relay L so that the subsequent release of the "oif button91 has no effect thereon. Then the second pair of contacts X open andthe first pair of contacts X close in the sequence named, removing theB+ voltage from the voltage divider 89' and grounding the positive endthereof through the resistor R 7 This resistor R is included in thecircuit of the first pair of contacts X of the second relay L, to retard7s hsdsssr, olt ge on a de l sg du t r PVC. It is to be noted that theanode voltage decreases gradually as a result of the combined action ofthis resistor and the resistance capacitance network 89. By so limitingthe rate of change of anode voltage negative voltage pulseselectrostatically induced on the control electrodes are prevented fromexceeding the value required to operate any of the previously restorednegative transconduetance pentodes P, P, P'", P' and P7.

After the second relay L is completely restored, the first relay Lrestores, thereby closing the second pair of contacts X thereof toground one end of the solenoid Y; of the first relay and to short outthe solenoid Y, of the second relay L Thereafter the first pair ofcontacts X opens thereby de-energizing the negative voltage conductorNVC. Thereafter the cathode heaters may be de-energized if desired byopening the power switch 84.

In order to cause the electrodes of the various circuits to becomede-energized in the proper sequence in the event of a power failure orin the event the control circuit 34 is tie-energized by opening the mainpower switch 84 before depressing the off switch 91, suitable time delaycircuits 97 and 98 are incorporated in the power supply 81 inassociation with the B+ and the B- terminals 85 and 86. Thus, in theevent that the power fails, the solenoid Y;, of the third relay Lbecomes deenergized just as if the off switch 91 were depressed, causingthe three relays L L and L to restore in the manner hereinbeforeexplained. In this case, in view of the fact that the voltages aremaintained at the 3-}- and the B terminals 85 and 86 by means of thetime delay circuits 97 and 98 until after the three relays L L and Lhave been restored, the counter circuit memory function is preserved. Itis to be noted that the cathodes of the various pentodes present remainthermally emissive until after the other electrodes of the pentodes havebeen de-energized because of the thermal lag of the cathodes even afterthe filament voltage is removed from the heaters.

Thus it is seen that I have provided a system for automaticallyde-energizing and re-energizing the elements of the counter circuit andstandardizer circuit in the proper time relation required to rememberand recall the last indicated count. While I have illustrated myinvention as applied to a counter, it will be apparent that in fact 1have discovered principles for remembering and recalling a condition ofany type of circuit. Clearly therefore many modifications may be made inthis circuit, and many other applications of the general principlesillustrated therein may be made without departing from the scope of myinvention.

Ring circuit construction In Fig. 6 I have illustrated the applicationof my invention to a ring circuit adapted to operate a scale-offourcounter. In describing this circuit the same symbols are used toindicate similar elements according to the system explained hereinabove,the same symbols being used herein as far as possible. This circuitincludes four sections S, S", S and 8"" arranged sequentially in a ring.Each section S includes a pentode P connected as a negativetransconductance device in the manner hereinbefore described. A controlcircuit GC including a three-winding operating transformer T and atwowinding restoring transformer T of the type hereinbefore described isincluded in each of the control circuits. A glow tube GL is connected inthe output of each of the pentodes in the manner hereinbefore describedin order to indicate whether the corresponding pentode P is in aconducting condition or a non-conducting condition.

In this ring circuit the anode A of each pentode P is connected to theanode voltage conductor PVC through the auxiliary winding W; of theoperating transformer T in the next section in sequence and through theprimary windings p of the transformer T in the last preceding section insequence. More particularly, the anode A of the first pentode P isconnected to the anode voltage conductor PVC through the auxiliarywinding W of the second operating transformer T and through the primarywinding P"" of the fourth restoring transformer T Also the anode A" ofthe second pentode P" is connected to the anode voltage conductor PVCthrough the auxiliary winding W, of the third operating transformer Tand through the primary winding p of the first restoring transformer TAlso, the anode A of the third pentode P" is connected to the anodevoltage conductor PVC through the auxiliary winding W;,"" of the fourthoperating transformer T and through the primary winding p" of the secondrestoring transformer T And also, the anode A" of the fourth pentode P"is connected to the anode voltage conductor PVC through the auxiliarywinding W;,' of the first operating transformer T and through theprimary winding P' of the third restoring transformer T A pulsestandardizer 30, shown only fragmentarily, of the type hereinbeforedescribed and a zeroing circuit (not shown) of the type hereinbeforedescribed, are associated with this ring circuit. The output pentode Pof the pulse standardizer 30 is connected to the anode voltage conductorPVC through the four primary windings W, of the operating transformer Tin series for applying pulses to the ring circuit.

Ring circuit-operation In the normal operation of this ring circuit, onesection operates at a time, and only the next section in sequence isprepared for operation and each time that a section operates, itrestores the preceding section in sequence.

More particularly, considering the detailed operation of the ringcircuit starting with a condition in which a zero count is indicated, inthis condition the fourth section 8" is operating and the first, secondand third sections 5', S", S are restored. Also, in this condition thecores M", M'", and M"" in the second, third and fourth operatingtransformers T T and T,"" are negatively magnetized in condition 3, andby virtue of the anode current flowing through the auxiliary winding Wof the first operating transformer T the core M of this transformer ispositively magnetized in com dition 4. And also in this condition glowlamp GL"" shines and the remaining glow lamps GL', GL", GL" are dark.

Thereafter, when the application of a pulse to the ring circuit from thepulse standardizer 30 is initiated, a unit current fiows through thefour primary windings W of the operating transformers T At this time themagnetization of the first operating core M reverses changing fromcondition 4 to condition 6 thereby applying a large negative pulse tothe pentode P' in the first section S and causing it to operate. Theresultant unit current flowing from the anode A of the first pentode Pthrough the auxiliary winding W of the second operating transformer Tcooperates with the current flowing through the primary winding W ofthis transformer from the pulse standardizer 30 to change themagnetization of its core M" from condition 3 to condition 2.Concurrently, the unit current flowing from the anode A of the firstpentode P through the primary winding p"" of the restoring transformer Tin the fourth section 8" restores the fourth section. When the fourthsection 5''" restores the unit current flowing to its anode A"" throughthe auxiliary winding W of the operating transformer T of the firstsection S and through the primary winding p' of the restoringtransformer T, of the third section 8' terminates, causing themagnetization of the first operating core M to change from condition 6to com dition 1. Also, as a result of the initiation of the unit 27pulse applied to the ring circuit, the magnetization of the operatingcores M'" and M"" in the third and fourth sections and 8"" change fromcondition 3 to condition 1.

Upon the termination of the first unit pulse current applied from thepulse standardizer 30, the magnetization of the second operating core M"is reversed, changing from condition 2 to condition 4, by the influenceof the current flowing through the auxiliary winding W;," of the secondoperating transformer T," from the anode A of the first pentode P. Atthe same time, the cessation of current through the primary windings W Wand W;"" of the other operating transformers T T and T causes themagnetization of the cores M, M, and M"" thereof to change fromcondition 1 to condition 3. As a final result of the application of thefirst pulse to the ring circuit, the fourth section 5''" thereof whichhad previously been operating is restored and the first section Sthereof which had previously been restored is operating and the secondand third sections S" and 5' remain restored. This change is indicatedby the darkening of the fourth glow lamp GL"" and the lighting up of thefirst glow lamp GL'. Only the second section S", in which the operatingtransformer core M" is magnetized in condition 4, is prepared foroperation by the next succeeding pulse.

Thereafter when a second pulse is applied to the ring circuit, thesecond glow lamp GL" lights up and the first glow lamp GL' is darkenedin the same manner. Similarly, when a third pulse is applied the secondglow lamp GL" darkens and the third lamp GL' lights up. And likewisewhen a fourth pulse is applied the third glow lamp GL' darkens and thefourth lamp GL" lights up, thus returning the circuit to its originalstate.

If it is desired to register counts which are multiples of the number ofsections in the ring circuit described, a plurality of similar ringcircuits are cascaded. For example, the primary windings of theoperating transformer of the second ring circuit are connected in seriesbetween the anode voltage conductor PVC and the anode A" of the fourthpentode P"" and in series with the auxiliary winding W;,' of the firstoperating transformer T, and the primary winding 11" of the thirdrestoring transformer T the four primary windings of the second ringcircuit being inserted at the point X. It is to be noted that theresultant arrangement is very similar to that previously described inFig. 1, that in Fig. 1 being an example of a cascade arrangement of tworing circuits each having two sections.

Ring circuit-Auxiliary circuit The various electrodes of the ringcircuit are energized by means of a power supply 81 and a controlcircuit 34 including a bank of relays L L and L in substantially thesame manner as those of the first stage of the counter of Fig. l. Theinter-connection between the pentodes P of the ring circuit and relays LL and L are illustrated in Fig. 6, identical parts being indicated byidentical legends to those used in Fig. 2. In this case the first pairof contacts X; of the third relay L are omitted since this counter hasonly one stage. With this arrangement, the ring circuit may bede-energized and then re-energized and the condition beforede-energization recalled by applying a series of four pulses theretofrom the output 40 of the pulse standardizer 30 in accordance with theprinciples hereinbefore set forth. In the event that a plurality ofcascaded ring circuits are utilized the control grids in the variousstage are de-energized and re-energized sequentially, and also in themanner hereinbefore described.

In connection with the zeroing of the ring circuit a biasing network 100is connected between the negative voltage conductor NVC and ground. Thisnetwork 100 ineluda. an upper resistor R and a lower resistor R thejunction between which is connected to a first biasing conductor B0which in turn is connected to the control grids CG, CG", and CG" of thefirst, second, and third pentodes P, P", and P'" through the associatedgrid circuits, GC, GC", and GC' in order to apply a normal biasingvoltage to said control grids. The control electrode CG'' of the fourthpentode P" is connected through the associated grid control circuit GC""directly to a second biasing conductor BC and thence through a normallyopen switch 102 to an intermediate point on the upper resistor R A timedelay network including a resistor R and a condenser C is connectedbetween the two biasing conductors RC and BC A condenser C and anormally open switch 103 are arranged in parallel across the lowerresistor Bag. A normally open pulsing switch 104 is connected to operatethe pulse standardizer 30 in the same manner as the pulsing switch 74 ofFig. 2.

The three switches 102, 103, and 104 are ganged to close in the ordernamed and to open in the reverse order. In utilizing this zeroingnetwork, when these switches are depressed, closure of the first switch1412 applies a high negative bias to the control grid CG"" of the fourthpentode P"", operating it in the event that it is not already operating.Closure of the second switch 103- grounds the control electrodes CG,CG", and CG' of the first, second, and third pentodes P', P", and P'"thereby restoring all of them if not already restored. Subsequentclosure of the third switch 104 applies a unit current pulse to theprimary windings W, of all of the operating transformers T Thereafterwhen the switches are released, the pulsing switch 104 opens, then thesecond switch 103 opens, and then the first switch 102 opens with thenet result that the ring circuit is in a condition corresponding to azero count and is ready to count pulses. In this condition the fourthglow lamp GL"" shines and the first, second and third glow lamps GL',GL", and GL' are dark. Also in this condition, the first operating coreM is positively magnetized in condition 4 and the remaining operatingcores M", M' and M"" are negatively magnv tized in condition 3.

Thyralron type c0unter--C0nstruction Referring to Fig. 7 there isillustrated an embodiment of my invention comprising a scale-of-fourcounter utilizing thyratron tubes arranged in pairs in two cascadedstages. The first stage includes first and second sections S and S" andthe second stage 111 includes third and fourth sections 8'" and 8"". Asbefore, in the description of Fig. 1, similar elements in the respectivesections are designated by the same letters to which superscripts andare affixed to indicate the section in which the elements are arranged.

Associated with each of the thyratrons TH is a grid control circuit GCwhich includes a three winding operating transformer T of the typehereinbefore described. In this instance the polarity of the secondarywinding W; of each of the operating transformers T relative to the othertwo windings W; and W thereof is the reverse of that used in Fig. l, inorder to enable the thyratrons TH to be operated by positive gridpulses. A current limiting resistor R is connected between the controlgrid CG of each thyratron TH and the integrating circuit IC across thesecondary winding W,.

The anodes A and A" of the first and second thyratrons TH and T arecoupled by a condenser C which enables each operating thyratron to berestored when the other companion thyratron operates. The anode A of thefirst thyratron TH is connected to a first anode conductor PVC, throughan inductor, or choke I, and a current limiting resistor R and theauxiliary winding W of the second transformer T". The anode A" ofthesecond thyratron TH" is connected to the same anode voltage conductorPVC, through a. similar inductor 1" and current limiting resistor Rthrough the first auxiliary winding W and through the third and fourthprimary windings W and W;"". A first glow lamp GL and a current limitingresistor R are connected between the anode A' of the first thyratron THand the first anode voltage conductor PVC; in parallel with choke I andresistor R In a like manner a condenser C couples the anodes A'" and A'of the third and fourth thyratrons TH' and TI-I"". And the thirdthyratron is connected to a second anode voltage conductor PVC throughan inductor I'" and a current limiting resistor R f and the auxiliarywinding W;"" of the fourth transformer T"". Also the anode A' of thefourth thyratron T is connected to the second anode voltage conductorPVC; through an inductor 1"" and a current limiting resistor R and theauxiliary winding W3, of the third transformer T'. A second glow lamp GLand current limiting resistor R are connected between the anole A'" ofthe third thyratron TH' and the second anode voltage conductor PVCOperation of thyratron type counter Considering the operation of thiscounting circuit, starting with a condition in which a zero count isindicated, it will be noted that in this condition the second and fourththyratrons TH" and T are conductng but the first and third thyratrons THand TH' are not, and both of the glow tubes GL and GL are dark. When thefirst pulse is applied to the counter at the input 112 of the firststage 110, a unit current flows through the primary windings W and W ofthe first and second transformers T' and T" momentarily. The resultantpositive voltage generated in the first secondary winding W, causes thefirst thyratron TH to operate, igniting the first glow tube GL, andreducing the voltage at the anode A of the second thyratron TH" to thepoint where this thyratron restores. When the latter thyratron TH"restores, the current previously flowing through the third and fourthprimary windings W and W terminates, inducing negative voltages in thesecondary windings W and W of the third and fourth transformers T' andT"". These negative pulses have no effect upon the thyratrons TH' andTH"".

When a second pulse is applied to the input 112, the second section S"operates, restoring the first section S and operating the third section8'. The operation of the third section 5'' causes the second glow tubeGL to shine and the fourth section 5" to restore, When a third pulse isapplied to the input 112, the first section S operates and the secondsection S" restores, the third and fourth sections 5' and 5''" remainingunaffected. The illumination of both the first and second glow tubes GL,and GL indicates the count of three. Upon the application of a fourthpulse, the second section S" operates, restoring the first section 8'and aperating the fourth section 8"". The operation of the fourthsection 8"" restores the third section 5". The resultant darkening ofboth the glow tubes GL and GL indicates that the counter has returned tothe zero condition.

Memory function of thyratron lype counter To illustrate how count imagesimpressed on the cores M permit this counter to be de-energized and thensubsequently re-energized and the prior count recalled, consider a casein which the counter indicates a count of 2 prior to shut-down, with thesecond and third thyratrons TH" and TH operating and the first andfourth thyratrons TH and Tl-l"" restored.

In de-energizing the counter under these conditions, first any inputpulse current which may then be flowing through the input "2 of thefirst stage 110 is terminated. Then the anode voltage is removed fromthe anodes A and A" of the first and second thyratrons TH and TH" byopening the circuit to the first anode voltage conductor PVC Thisterminates the current previously flowing to the anode A" of the secondthyratron TH" through the third and fourth primary windings W and W;"".Then the anodes of the third and fourth sections 8' and 8"" aredisconnected from the source of anode voltage by opening the circuit tothe second anode voltage conductor PVC- Thereafter, normal bias voltageis removed from the grids CG of all thyratrons TH, and then, if desired,the power to the cathode heaters H associated with the grounded cathodesK is turned off.

In re-energizing the counter the voltages to the electrodes of thethyratrons are applied in the reverse order from which they werepreviously removed. Thus, first the heaters H are connected to thesource of power, then the proper negative bias is applied to the gridsCG and then the anode voltage is applied to the anodes A' and A"" of thethird and fourth thyratrons TH'" and TH"" and then to the anodes A andA" of the first and second thyratrons TH and TH". Upon completion ofthis sequence none of the thyratrons are conducting. When in thiscondition a count image is impressed upon the set of magnetic cores in amanner similar to that hereinbefore described and the counter is readyto recall the previous count by the application of four pulses to theinput 112 of the first stage 110.

In order to zero this counter, a unit current is applied from the pulsestandardizer (not shown) to the input 112. of the first stage by closinga first switch such as. indicated at 113, connected in the input circuitof the; pulse standardizer in a manner comparable to the pulsing switch74 in Fig. 2. Thereupon while these contacts arestill closed the gridcircuits of the second and fourth thyratrons T and TH'' are grounded byclosing a second switch 114 corresponding in function to the groundingswitch 75 in Fig. 2. These switches are opened, in the reverse order,resulting in the operation of the second and fourth sections S" and S""and the restoration of the first and third sections S and S'" andmagnetizing the cores M in such a way as to prepare the counter forcounting.

Thyratron type counterA uxiliary circuit The proper sequentialenergization and de-energization of the various electrodes is preferablyaccomplished by means of two relays L and L The first relay L is of theslow-to-restore type and comprises first and second pairs of contacts Xand X which are normally open and which act in the order named when therelay operates and in the reverse order when it restores. The first pairof contacts X are included in a circuit which connects the grids CG ofthe various thyratrons TH through biasing conductor B0; to a terminal towhich a normal negative bias voltage is applied. The second pair ofcontacts X is included in series with a normally closed of? switch 121between the solenoid Y of the second relay L and the power mains. Thiscircuit is preferably connected on the low side of the main power switchof the power supply from which various voltages are derived for thecounter, namely the voltages for the bias terminal and the B+ terminaland the power for the heaters.

The second relay L includes first, second, third and fourth normallyopen contacts X 13, X14. and X which act in the order named when thesecond relay operates and which act in the reverse order when this relayrestores. The first and second pairs of contacts X and X are included inseries with the second and first anode voltage conductors PVC and PVC,respectively and a common point 122 between the solenoid Y, of the firstrelay L and the normally open on button 123 connected between thatsolenoid Y and the B+ terminal 124. The third pair of contacts X isarranged in a circuit between this common point 122 and the output ofthe pulsestandardizer in series with the primary windings W and W of thefirst and second transformers T and T".

